1. Field of the Invention
The present invention is directed generally to binders for porous composite particle blocks and, more specifically, to binders for porous composite carbon block water filters.
2. Description of the Related Art
Typically, a composite block filter is a hollow core cylindrical block of bonded, activated carbon grains. Water flows through the perimeter of the carbon filter, into the center core and on to the user. It is the interaction of water with the carbon surface that removes impurities.
However, carbon alone cannot remove all the impurities of interest. Often additional active media (actives) are mixed with activated carbon and binder particles before a porous composite block filter is formed. It is desirable to use actives in fine granular form to optimize the surface area per unit volume. When a mixture of activated carbon grains, binder particles, and fine granular actives is heated and pressed to form a porous composite block filter, the carbon grains and the similarly-sized binder particles form a basic network structure. Many of the much smaller active granules are subsequently lost as they fall out of the block through channels within the network.
Accordingly, there is a need for improved processes and materials for making porous composite block filters that can include active grains of various sizes.